docs: def make_interval(long_name, short_name):
      """ Create an interval segment """
      return Group(
          Regex("(-+)?[0-9]+")
          + (
              upkey(long_name + "s")
              | Regex(long_name + "s").setParseAction(upcaseTokens)
              | upkey(long_name)
              | Regex(long_name).setParseAction(upcaseTokens)
              | upkey(short_name)
              | Regex(short_name).setParseAction(upcaseTokens)
          )
      ).setResultsName(long_name)